Manual steering rack reccomendations

[Kate T]

I am full on parts collecting for a scratch built gt40 chassis,

But I want a kit of the mechanical parts ready and collected first.

Tried and tested corsa B column, but I am at a loss whether the B rack will work or if there is an awesome easily available one I am over looking.

I understand hydraulic racks with disconnected pipes won't work?

Preferably modern used from a breakers, LHD, used if possible because I am trying hard to keep the cost down to reasonable for the parts that I can because there is still so much to expensive stuff to buy.

It doesn't need to be a quick rack, this is for a road only car.

 

[Fred/Belgium]

If you have a GTD
THEN THE GRANADA OR CONRTINA STEERING SHOULD WORK.
You may find it on ebay co uk with an avg price of 100 ukp.
RHDS
FRED

 

[Kate T]

Cheers, but LHD is the issue. Not a GTD either, but scratch made chassis so the mounting is immaterial.

And it is a long time since I saw one of those early Fords round here. The change in the environment laws has meant pretty much all the scrap yards I know who had old cars like that have crushed the lot and closed down.

Sad really.

On Thursday I was planning to try the last large and decent yard around that has older vehicles, the owner does a really good price if you can put together a bunch of parts at once if you take them off yourself, I think he has 6000 vehicles being broken on 40 acres. 3 hour drive each way.

Just after some ideas of good strong manual racks, most of the larger saloons seem to have hydraulics, and the smaller cars with electric assist steering I am unsure if the steering rack would be strong enough for a GT40.

 

[Ryan L]

i just googled "BMW power steering delete" and this popped up as the first option
https://www.condorspeedshop.com/products/aluminum-power-steering-delete-block-plate-e30


and then "MX5 power steering delete"
https://www.flyinmiata.com/tech/depower.php

hope that helps.

remember that some cars had very long steering arms on the knuckle/upright, so a rack out of those cars will be commensurately quicker than say an equivalent car with short steering arms.

Your key consideration is likely to be what angle the pinion shaft exits the rack on to allow it to clear the accelerator brake and clutch pedals. I am going to have a look at a BMW E46 rack (purple tag version) for mine when i get a bit further along. potentially de-powered, however i may also fit a opal (zafira) or ford (focus) electric pump for power steering.

Ryan

 

[Ian Anderson]

http://www.rallydesign.co.uk/product_info.php?products_id=10620

Left hand Drive Manual Steering rack

 

[Mike Pass]

The important thing is to avoid bump steer. If the steering arm swivel locations are not compatible with the wishbones pivot locations the upright will be turned as the suspension rises and falls. This is bump steer and will make the car nasty to drive as ever time it hits a bump or a dip it will dive left or right and a fast ride down a bumpy road could be a bit scary.
There are various ways of avoiding bump steer but the simplest way to get somewhere near is as follows. Try to get the steering arm swivels and the wishbone pick up points in the same plane. i.e. a flat sheet would pass through all these points.
To check for bump steer attach a cheap laser pointer to the hub pointing horizontally forwards. Aim the pointer at a vertical surface such as a wall with a big sheet of paper or card stuck on it. Then move the suspension through the normal range of movement and mark the position of the laser dot every 1cm or so. If there is no bump steer the line plotted will be straight and vertical. With bump steer it will be at an angle and/or curved. Pay particular attention to the straightness of the line around the point where the suspension will be at the normal ride height. Because the suspension arms and the steering arms move in an arc you can never totally eliminate all bump steer. You just need make it little enough to be insignificant especially around the normal ride height position.
Also a bit of research on the subject of roll centre location and it's movement as the suspension moves at the design stage can help to make the car more stable in feel and nicer to drive. There is a fair bit of info around on how to do this using a plywood model of the suspension geometry - often called a "string computer".
Cheers
Mike

 

[Scott Davis]

I couldn't find a rack that would fit my application so I just ordered a custom one. Like MikeP said, I think bump steer is the real thing to worry about. I used a laser to create a plane that intersected the attachment points of the upper and lower control arms (pivot points). Then estimated the height I wanted the rack and took the measurement. Pretty easy to take the measurements and put them on paper or a CAD program. Maval and Unisteer can both make custom racks and the price is nearly identical to off the shelf racks @ $400 US. The big downside is the wait. They have grown significantly and are very backed up (the big car manufacturers get their time). If you can find something that has the correct inner and outer tie rod point for appropriate geometry (bump steer) you can save yourself 5 months waiting for a custom one.

 

[Kate T]

Well, spent half of yesterday looking at cars in a breakers, there is a cheap one just down the road who always does me great prices, but not a lot of choice.

I will go with the stock corsa b rack for the moment, it almost certainly will need replacing, but it will allow me to get a head start on getting the steering geometry sorted. See what doesn't work so I can see what does better.

70 euro just with the corsa B EPAS Column, switches , steering wheel ( for the IVA) , Ujs and rack.

I never knew you could do a power steering delete on hydraulic racks, one of those times where a lack of knowledge hinders my ability to ask the right questions. That really does open up my options, I may even have a power steering rack suitable in the barn from an old car.

Same breakers yard has ( I think) 2 X Audi 01E trans axles. I cannot at this point work out ratios, both early A4s one TDi 1.9 and the other a 2.3 petrol. but at 150 euro with drive shafts, bearing carriers , hubs and mounts, it will do at least as a mock up set.

I don't want to start yet another o1E thread on here.

I am thinking of using the Audi front hubs and modifying them for IRS. Has anyone done that? I would have thought the rear axle weight of a GT40 was close the the stock A4 front, so the wheel bearings will be strong enough. My target horsepower isn't high. Mid 350HP.